Process for increasing the bulk of multifilament yarn



Dec. 1', 1970 A. 1.. BREEN AL PROCESS FOR INCREASING THE BULK OFMULTIFILAMENT YARN' Filed Oct. 24. 1967 5 Sheets-Sheet l INVENTORS ALVINL. BREEN HERBERT G. LAUTERBACH A RNEY Dec. 1, 1970 L, BREEN El'ALPROCESS FOR INCREASING THE BULK OF MULTIFILAMENT YARN Filed Oct. 24.1967 5 Sheets-Sheet 2 FIG. l5

INVENTORS ALVIN L. BREEN HERBERT G. LAUTERBACH ATTOR EY Dec. 1, 1970BREEN ET AL PROCESS FOR INCREASING THE BULK OF MULTIFILAMENT YARN FiledOct. 24, 1967 5 Sheets-Sheet 5 FIG. 4

INVENTORS v BY a (3 ATTOR EY NH M E m U A WL V. LG T R E B R E H Dec. 1,1970 BREEN EI'AL 3,543,353

PROCESS FOR INCREASING THE BULK OF MULTIFILAMENT YARN Filed Oct; 24,1.967 5 Sheets-Sheet 5 s E E 2 50 I00 I50 200 250 500 550 450 FILANENTBREAK ELONGATION, lo

zs|o|4|a222eaoa4 TOTAL TAKEUP, 0mm FlG l9 /o DYE IN FIBER 0 50 I00 I50200 250 300 mum BREAK ELONGAT|0N,% ,NVENTORS ALVIN L. BREEN HERBERT G.LAUTERBACH U.S. Cl. 2872.12 17 Claims ABSTRACT OF THE DISCLOSUREProcesses and apparatus are disclosed for treating a bundle ofcontinuous filaments to produce a multifilament yarn of greatlyincreased bulk, wherein the filaments have a unique nonhelical crimp.The treatment also improves the dyeing characteristics. A hotcompressible fluid, such as air or steam, is jetted to form a turbulentregion. Yarn or zero or very low twist is fed through the turbulentregions, is plasticized by the hot fluid and is led away from the fluidand cooled. The yarn feed and take-up speeds, temperature and otherconditions are adjusted to provide the desired amount of crimp. Theexamples illustrate a wide variety of treatments for different purposes.

REFERENCES TO RELATED APPLICATIONS This is a continuation-in-part ofcopending application Ser. No. 698,103, filed Nov. 22, 1957 nowabandoned, and Ser. No. 43,897 filed July 19, 1960, and now abandoned.Products referred to herein are claimed in U.S. Pat. No. 3,186,155 datedJune 1, 1965, which was filed as a continuation-in-part of said firstmentioned application.

This invention relates to a process for treating a bundle of filamentssuch as yarn or thread to produce a multifilament yarn of greatlyincreased bulk. More particularly, the invention relates to theproduction of a bulky yarn composed of a plurality of substantiallycontinuous individually crimped filaments having a randomthree-dimensional curvilinear configuration and improved level dyeingcharacteristic and faster dyeing rate.

Artificial fibers are normally produced most easily as continuousfilaments. These continuous filament yarns are very strong because ofthe absence of loose ends that are unable to transmit imposed stresses.Their extreme uniformity and lack of discontinuity, however, makesconventional continuous synthetic filament yarns much more dense thanyarns made from synthetic staple fibers. The production of yarn fromstaple fibers, however, is time consuming and requires a complex seriesof operations to crimp the fibers, align the fibers into an elongatedbundle and then to draw the bundle to successively smaller diameters.The final spinning operation, which involves a high degree of twist,finally binds these discontinuous fibers together to product a coherentyarn with considerably increased bulk. The occluded air spaces give thema lightness, covering power, and warmth-giving bulk not normallypossible with continuous filament yarns. Thus to get staple fibers thatcan be processed on conventional wool or cotton spinning equipment, ithas been the practice to cut continuous filament yarns such as rayon,acetate, nylon, as well as the polyacrylic and polyester fibers intoshort lengths for spinning into staple yarn.

Recent developments in the textile industry have provided useful routesfor improving the bulk and covering power and recoverable elongation ofcontinuous filament yarns without resorting to the staple spinningsystems of 3,543,358 Patented Dec. 1, 1970 the prior art. A well-knownprocess for making stretch yarn involves the steps of twisting,heat-setting and then backtwisting to a low final twist level. Anotheryarn of improved bulk is prepared commercially by the steps of twisting,heat-setting and backtwisting on-the-run using a false-twistingapparatus. This end product can be further modified by hot relaxing toimprove the bulk and handle. Still another bulk yarn is being preparedby the well-known stuifer box technique wherein the yarn is steamed toheat-set while it is in a compressed state in the stuffer box.

All of these yarns of the prior art are produced by a process which hasthe common elements of deforming the yarn mechanically and thenheat-setting either with or without an after-relaxation step. It was notuntil the recently disclosed product in U.S. 2,783,609 to Breen, issuedMar. 5, 1957, and its process of manufacture became known that anentirely new technique became available for improving the bulk ofcontinuous filament yarns. This technique involves exposing afilamentary material to a rapidly moving turbulent fluid, therebyinducing a multitude of crunodal filament loops at random intervalsalong the individual filaments. These loops and snarls of entangledloops increase the bulk of the continuous filament yarns considerablyand result in fabrics of improved cover, bulk, handle and the like. Withthe invention of Breen, a new tool is available for the bulking offilamentary structures, i.e., a turbulent fluid. Fluids, of course, havebeen used for yarn treating in many of the prior art operations such asdrying, extracting, transporting and the like. Until the invention ofBreen, however, they had not been used to entangle, convolute and bulk afilamentary material. It has now been discovered, however, that a newprocess utilizing the turbulent fluid technique results in new yarnproducts that have certain unique properties not heretofore disclosed inthe art.

It is an object of the present invention therefore to provide continuousfilaments and continuous filament yarn having a bulkiness greater thanstaple yarn spun from comparable fibers. Another object is to providemultifilament yarn resembling spun staple in its desirable lightness,covering effectiveness and warmth-giving bulk but retaining thecharacteristic continuous filament freedom from loose ends, fuzzinessand pilling. A further object is to provide a process for preparingcontinuous filament yarn having a bulk greater than that of comparablestaple yarn without abrading or cutting the constituent filaments. Astill further object is to provide a process which is suitable forrapidly and economically treating ordinary multifilament continous yarnto greatly increase the bulk without the use of moving mechanical partsother than in the windup. It is also an object to prepare a bulkyfilamentary material especially useful for the pile component of pilefabrics. Other objects include the provision of continuous filament yarnhaving greater bulk than staple yarn together with increased uniformityof dyeing rate with low elongation and very low pilling tendency. Otherobjects will appear as the description of the invention proceeds. 1

The objects are accomplished by feeding a yarn bundle which has no morethan 1 turn per inch (t.p.i.) of bundle twist to a turbulentplasticizing region formed by a stream of a compressible fluid jetted ata temperature of at least 300 F., then cooling the filaments under lowtension and taking them up at a rate which provides at least 30%overfeed to the stream. Under these conditions the filaments are crimpedindividually in a nonhelical, threedimensional, random, curvilinierconfiguration which persists after tensioning and hot-wet relaxation.

The amount of twist in the feed yarn has a surprising effect on thefilament crimp and yarn bulk of the products, whereas twists of l t.p.i.or less provide a nonhelical,

random filament crimp and high yarn bulk. However, when twists of 2t.p.i. or more are used with otherwise comparable conditions, a fairlyregular helical-type filament crimp is obtained and the yarn product isrelatively compact with protruding surface loops which impart a degreeof voluminosity without much bulk. Feed yarns having 1.5 t.p.i. or lesstwist provide more random crimp and greater bulk. This indicates thatthe presence of normal yarn twists will prevent adequate filamentseparation and movement in the turbulent fluid. The filaments must havesubstantial freedom to whip about during the bulking operation in orderto achieve the antique crimp and high bulk.

The invention and the manner of carrying it out will be more clearlyunderstood by reference to the drawings in which:

FIG. 1 is a schematic perspective view of apparatus suitable for theproduction of the bulky yarn of this invention; FIG. 2 is a schematicperspective view of a variation of this equipment suitable forstretching the yarn and bulking it in successive steps withoutintermediate packaging; FIG. 3 is a schematic perspective view ofsimilar equipment adapted to spinning, drawing, and bulking insuccessive steps Without intermediate handling or packaging; FIGS. 4, 5,6, 7, 8, 9, 10, 11 and 12 show various jet devices useful in theproduction of the yarn of this invention; FIG. 13 is a cross-sectionalview of the bulky yarn of this invention; FIG. 14 is a longitudinal viewof single filaments modified in accordance with the process of thisinvention; FIG. 15 is a longitudinal view of a multifilament yarn ofthis invention; FIGS. 16 and 17 show variations of the multifilamentyarn product of this invention; FIG. 18 shows a single filament producedin accordance with this invention from a fiber of nonround crosssection; FIG. 19 shows a graphical relationship between the dyeing rateof the product in this invention and its break elongation; FIG. 20 showsa graphical relationship of the pilling index of the product of thisinvention and its break elongation; FIG. 21 shows a graphicalrelationship of compressional characteristics versus weight for pilecarpets made of the yarn of this invention compared with conventionalstaple yarn; and FIG. 22 is an illustration of a fiber cross section forpreparation of a preferred carpet yarn.

In FIG. 1 the moving threadline to be treated 31 is passed through guide32, between feed rolls 33 and 34, over guide 35, through fluid jet 36,over guide 37, through quench tube 38, provided with cooling fluidthrough opening 39, through guide 40, to guide 43, or alternatelybetween feed rolls 41 and 42. Traverse guide 44 may be used todistribute the bulky yarn on package 46 driven by roll 45 or package 46may be a roll which with 45 is used to feed yarn to piddle tube 47provided with aspirating tube 48 depositing yarn in container 49.

FIG. 2 shows undrawn yarn 51 passing continuously between feed rolls 52and 53 around pin 54 to draw roll 55 having two cylindrical surfaces 56and 58. Several wraps of yarn are placed about surface 56 and idler roll57. The yarn is then passed continuously through guides 60 and 61, jet62 and over guide '63. Several wraps of the bulky yarn from the jet areplaced about roll surface 58 and idler roll 59. Idler rolls 57 and 59are positioned with their axes at a slight angle to the axis of roll 55to spread the yarn wraps. From roll surface 58 and idler roll 59, theyarn is passed continuously through traverse guide 64 to package 65driven by roll 66.

In FIG. 3 filaments 70 from spinneret 71 quenched asymmetrically by coldfluid directed to the face of the spinneret by fluid nozzle 72 areconverged at guide 73 and passed around rolls 74. The yarn iscontinuously drawn on draw pin 75 by wraps around rolls 76 moving athigher speed and is then fed through guides 78 and 79 and jet 80. Thebulked yarn leaving the jet is passed around guide 81 and rolls 82.Quenching device 84 cools the yarn or alternatively it is cooled by theflow of cold 4 air through box 87 around cooling rolls 82, 85, and 86.From the cooling rolls, the yarn is fed continuously through traverseguide 88 to package 89 driven by roll 90.

FIG. 6 is a jet suitable for the practice of this invention, consistingof body member 95, orifice member 96, held in place by clamp 97, andscrew 98. This jet is illustrated more fully in co-pending applicationSer. No. 604,564 filed by Hall on Aug. 16, 1956, now Pat. No. 2,958,112.The passage through orifice member 96 consists of cylindrical opening100, connecting with concentric cylindrical opening 101, and outwardlytapered opening 99, characterized by the angle a. Yarn tube member 102,supporting hollow needle 103, in hole 104, with cutaway section giving alip 105, is supported in body member 95, in an adjustable fashion byscrew tightened in tapped hole 106. The compressible fluid is applied tothe nozzle at 107, and the yarn is fed to needle member through hole108.

FIG. 7 is another jet consisting of body member 110, and yarn guidemember 111, with perforated disc 112, and fluid entrance 113. Yarn isfed to this nozzle through opening 114.

FIG. 8 is a similar jet consisting of body member 115, yarn guide 116,and orifice 117. Compressible fluid enters the body member throughopening 118, and the yarn enters through opening 119.

FIG. 9 is a similar jet particularly adaptable to multiple end operationwhere precise temperature control is desired from position to position.It consists of jet body 121, with opening 122 for the turbulent fluid,and replaceable orifice 123. Yarn guide member 124, provided with yarnopening 125, is machined so that tip 128 is eccentric to the jet axis.Jet body 121 is sealed in manifold 129 by gaskets 126, and flanges 127.

FIG. 10 is a simplified jet suitable for the practice of this inventionconsisting of body member 130 with drilled holes as shown to provide aT-shaped intersection at 131. Thin-walled tubing 132 connecting tocompressible fluid supply through adapter 133 serves as a combinationconduit and heater for the compressible fluid. Similar thinwalledtithing 134 attached to body member 1330 serving as a yarn preheater isprovided with yarn entrance 135. A high amperage electrical currentapplied between lugs 136 and 137 heats the compressible fluid passingthrough tube 132 by virtue of the electrical resistance of the tubing.Similarly, high-amperage current applied between lugs 138 and 139provides additional heating to the turbulent fluid exhausting acounter-current direction to the thread line moving from toward 131.This arrangement preheats the yarn so that it is in a desirablyplasticized state as it traverses the zone of greatest turbulencebetween 131 and 141. Turbulent fluid exhausting preferentially fromorifice 141 produces the desired bulking action. Insulation preventsexcessive heat loss from tubes 132 and 134 and also tends to supportthese fragile elements. This unit is particularly useful for treatingyarns at very high speeds in the range of 5001000 y.p.m. or more. FIG.11 shows the intersection 131 of the jet in cross section of FIG. 10. Itis to be understood that other devices employing heated plates or rollsmay be substituted for the preheater of FIG. 10. Similarly, thepreheating fluid could be a hot gas applied by an auxiliary nozzle or ahot liquid applied in an open bath or semi-confining tube. Such deviceslikewise may be made as an integral part of any of the fluid nozzles ofFIGS. 6, 7, 8, 9, or 12 or those described in the reference patents andpending applications, for example, application Ser. No. 604,564 filed byHall on Aug. 16, 1956, now Pat. No. 2,958,112, and U.S. 2,783,609 toBreen, issued Mar. 5, 1957.

FIG. 12 shows one form of jet particularly useful for the practice ofthe process of this invention as indicated in FIG. 3 Where the threadline being treated is taken directly from a spinning operation. In thiscase, body member is split into two similar portions. Likewise, yarnguide member 143 is split into similar parts, laying open the yarnpassage 144 and orifice 145. For stringup, these parts are held in theopen position by hinge 146. During the bulking operation, the parts areheld in a closed position by hook 147 and pin 148. Screws 149 are usedto adjust the depth of yarn guide member 143 within body piece 150. Anadjustment of the opposing yarn guide members 143 to slightly differingdepths produces a desirable eccentricity of the turbulent fluid flowpattern. Other forms of jets similar in principle to FIG. 12 but havingrotating or sliding parts or other mechanisms to provide access to theturbulent fluid chamber are likewise useful in the process of thisinvention.

FIG. 13 is a thin cross section of the yarn showing short lengths offilaments in randomly disposed arrangement. Fibers at points a show arandom wrapping effect which in some cases improves the cohesiveness ofthe yarn bundle Without inhibiting its bulkiness and stretchingproperties. The freedom from protruding loops indicated here givesdesirable improvement in yarn handling characteristics and freedom fromsnagging problems in end use form. The yarn cross section was made bysupporting the sample in a transparent mounting of polymethylmethacrylate prior to sectioning so as to hold the short lengths offibers in position.

FIG. 14 is an illustration of the individual filaments of the invention.Points show what appear to be angular crimp form. This is intended torepresent a region where the filament path is in the general directionperpendicular to the plane of the illustration causing apparentdistortion of the curvilinear form.

The above statements applying similarly to the filaments comprising theyarns illustrated in FIGS. 15, 16, and 17.

For certain uses where subdued luster and tactile dryness are desiredthe preferred product of this invention should be made from fibershaving a non-round shape of critically selected character. In carpetyarns, for example, it has been found that the approximately symmetricalcross-sectional form indicated in FlG. 22 is preferred. This is definedin terms of a modification ratio which i the ratio of the diameter ofthe enscribing circle D to the inscribed circle a.

A desirable property of the product of this invention based on thesenon-round fiber forms is illustrated in FIG. 18. Here the fiber has notonly the random three-dimensional, non-helical, curvilinearconfiguration, but is also formed into a randomly twisted configuration,portions of which are in an S direction with other portions being in a Zdirection.

To determine the extent of the random twist modification of theindividual fiber, a specimen is mounted between microscope slides withsufficient tension to hold the fiber axis in an approximately straightcondition but a tension low enough that the twist is not appreciablyreduced. The angle is then measured between imaginary lines followingthe outermost points of the filaments and the filament axis at a numberof points sufiicient to provide a meaningful average. This average angleshould be at least 1. There will be points where the angle isessentially zero where the twist reverses direction. Other points arefound where the angle is considerably greater than the average value. Inwell modified samples maximum values in the order of 30 are observed andthe average may be as much as or more.

Since the twist of each filament is random along its length, a yarn madeup of a group of these filaments is prevented from packing in a closelynested configuration. This is true even when considerable tension isapplied to the yarn sutficient to straighten the random curvilinearcrimp configuration. This latter property is particularly useful inincreasing the bulk of tightly Woven fabrics where loom tension andfabric construction tends to reduce the bulking effect due to crimp. Therandom twist is likewise useful in highly crimped pile yarns of bulkyknit structures where it tends to reduce objectionable glitter or lusterassociated with light reflection from the fiber surfaces.

Other methods of producing this random twisted or convoluted structureare described in copending application Ser. No. 675,728, filed Aug. 1,1957, by Breen and Covell, and now abandoned.

In the preferred process of this invention, filaments and yarns meetingthe above objects are provided by a process in which a .stream ofcompressible fluid at a temperature above the second order transitiontempera ture of the polymer of which the filament is made and preferablyat least about 300 F. is vigorously jetted to form a turbulentplasticizing region. Under these conditions the yarn temperature isabove the cold point as described more fully hereinafter and below themelting point of the yarn. Yarn having substantially no twist ispositively fed at a rate greater than the yarn take-up speed into thefiuid plasticizing stream so that the yarn is supported by it andindividual filaments are separated from each other and crimpedindividually by whipping about in the hot turbulent plasticizing region,and is then cooled while being maintained at low tension to set theconvolutions. During the jetting treatment, filament shrinkage occursbecause of the heat transmitted to the fibers. The process elements suchas temperature, pressure, fluid flow, yarn speed, tension, and wind-upspeed are adjusted so as to give a final yarn denier (measured inrelaxed form after hot-wet relaxation) at least 30% greater than thefeed yarn denier.

The crimped filaments are withdrawn from the plasticizing zone by thefluid exhaust and the take-up rolls. The filaments pass through acooling zone before or after the take-up rolls to prevent furtherplastic flow and to insure retention of the crimp while maintaining theyarn in a substantially relaxed and tensionless condition. Aftercooling, the yarn may be tensioned to remove any fiber loops, eliminateany packing of filaments and to improve the bulking characteristics ofthe yarn. Tensioning is desirable also for forming a suitable package onany wind-up device. Tension applied in pulling the yarn away from thejet or in winding the yarn on a package appears to cause some temporaryremoval of fiber crimp, but this crimp is subsequently recovered whenthe yarn is relaxed and boiled-off. Stable crunodal loops are avoided orat least kept to a minimum by control of the process conditions sincesuch entangled loops prevent maximum bulk from being obtained in theyarns. The crimped yarn, of course, may be cut into staple after passingthrough the turbulent hot fluid. This process, therefore, provides ahighly productive way of crimping tow which is to be used in stapleproducts. This process may also be used for setting dyes in the yarn. Ayarn padded with dyes may be either treated with a turbulent fluid toset the dyes in the fiber by diffusion through the fiber or it may betreated with a turbulent fluid to simultaneously bulk the yarn and setthe dyes.

Bulky yarn can be prepared by the process of this invention fromanyplasticizable fiber. The process is ap plicable primarily to continuousfilament yarns and multifilament yarns in particular althoughmonofilaments can also be crimped in the same manner. Staple yarns canalso be processed to give products of greatly increased crimp and bulkparticularly in the surface fiber.

The products of this invention are different in fundamental physicalstructure from any of the bulked yarns described in prior art. Duringthe jetting treatment, a most surprising shrinkage of the filaments andrelaxation of the molecules making up the filaments occur. When jettedunder optimum conditions, this shrinkage and relaxation far exceeds thatwhich occurs when the yarn is exposed to the same fluid at the sametemperature and under zero tension for a long period of time withoutagitation. This dynamic relaxation is responsible for a considerableamount of deorientation of the molecules and an increase incrystallinity. In addition, there is a large increase in dyereceptivity. In retrospect, it is now believed that the turbulentconditions in the jet subject each section of the filament toinnumerable and successive stressings and complete relaxations. Theserepeated stressings are believed to supply a part of the energy ofactivation needed to break bonds between the molecules making up thefilaments and thus to permit more complete relaxation of the moleculesduring the subsequent short intervals when the sections of the filamentare under no tension, or perhaps even under compression, than wouldoccur if the filaments were not subjected to multiple stressings. Thus apractical way has been found to accomplish a very valuablereorganization of the molecular structure of the filament which wouldotherwise be utterly impossible to accomplish.

The higher filament temperatures under relaxed conditions and therepeated stressing cause the amorphous molecular structure to open-upgiving more lateral space between molecules and greater distance betweencrystallites along the fiber axis. The great changes in the amorphousmolecular structure are shown clearly by low angle X-ray patterns usingthe techniques described by W. O. Statton, J. Polymer Sci. 22 385(1956). This new opened-up conditions, plus the deorientation whichoccurs, gives fibers with greatly improved dyeing rate not heretoforeencountered in textile yarns. The dyeing rate is increased about 50% to150% by the process of this invention and there is no change in thechemical composition of the fiber during treatment. Of course, moderateimprovements in dye rate have been shown in prior art by relaxed heattreatment, but increases in dye rate greater than 50% have notheretofore been encountered. In addition, the uniform turbulent heatingin the present process permits much higher average fila menttemperatures to be obtained since there is no danger of surfacefilaments being heated above their melting point.

All commercial procedures for manufacturing synthetic fibersinadvertently subject a portion of the yarn or certain segments of aportion of the yarn and filaments to plucks or other stresses as, forexample, when processing with fluids or passing over guides, at whichcauses these yarns or segments to dye at a diflerent rate and/ or to adifferent depth relative to the bulk of the yarn. The dynamic relaxationemployed in this invention eliminates most of the non-uniformities instructure caused by these plucks and stress and thus the treated yarnshave much more uniform dyeability along and across the bundle than canbe obtained by non-turbulent radiant heating or by contact with heatedmechanical surfaces. The yarns prepared by the process of this inventiontherefore have better dyeing uniformity than bulk yarns prepared by thetwist-heat set method, by s-tuffer-box crimping, or by other processesknown in the art.

The products of this invention assume a three-dimensional, non-helical,random, curvilinear configuration. This structure is different from thebulked materials prepared by the various twist-setting operations, sincethese have predominantly a helical and regular type of filamentarydeformation. It is different also from those prepared by the well-knownstuffer box technique, since the latter are characterized by a regularand reversing or saw-tooth planar type of crimp. Because of theturbulent and random fluid currents in the treating chamber of thesubject process, the crimp in the subject products is three-dimensionaland random in crimp amplitude and period. The high degree of turbulencein a confined space results in a very high crimp level, and acurvilinear rather than rectilinear, saw-tooth, helical or crunodal looptype of filamentary configuration. The crimp is permanent to normalfiber processing conditions and will persist in filaments taken from theyarn bundle. On exposure to hot water, marked increases in crimpamplitude and frequency are obtained. The useful products of thisinvention have a crimp level in excess of per inch, and preferably aboveper inch. They may even be as high as 70 or 80 crimps per inch.

The process of this invention can be used to crimp and bulk any naturalor synthetic plasticizable filamentary material. Thermoplastic materialssuch as polyamides; e.g., poly(epsilon caproamide) andpoly(hexamethylene adipamide), cellulose esters, polyesters; e.g.,polyethylene terephthalate, polyvinyls and polyacrylics; e.g.,olyethylene and polyacrylonitrile, as well as copolymers thereof can becrimped to give the three-dimension, random, curvilinear configurationdescribed herein. While the preferred form of material is continuousfilaments, the process and resultant improvements occur with stapleyarns as well. Both types of materials can be made into bulky yarns andfabrics having improved bulk, covering power (opacity) and hand.

This process is useful for both monofilament and multi filament yarns intextile deniers as well as the heavier carpet and industrial yarn sizeseither singly or combined in the form of a heavy tow. Fine count andheavy count staple yarns can be processed both singles and plied. Theprocess and product are also not restricted in the case of the syntheticmaterials to any one particular type of filament cross section.Cruciform, Y-shaped, delta-shaped, ribbon, and dumbbell and other suchfilamentary cross sections can be processed at least as Well as roundfilaments and usually contribute still more bulk than is obtained withround filaments.

The turbulent fluid used to treat the filamentary material may be air,steam. or any other compressible fluid or Vapor capable of plasticizingaction on the yarn provided that it has a temperature above the secondorder transition temperature of the filament. Hot air will givesufficient plasticization in the turbulent region for many fibersalthough it may be desirable for certain fibers to supplement thetemperature eflfect with an auxiliary plasticizing medium. Actually,steam is preferentially used in the subject process since it is a cheapand convenient source of a high pressure fluid with a compoundplasticizing action.

The temperature of the fluid medium must be regulated so that the yarntemperature does not reach the melting point of the fiber. However, withfibers made from fusible polymers, the most effective bulking and thegreatest productivity is obtained when the temperature of the turbulentfluid is above the melting point of the fiber. In this case the yarnspeeds should be great enough so that melting does not occur. Because ofthe great turbulence and the high heat, yarns are heated rapidly.Temperatures lower than the second order transition temperatures (T ofthe yarn material should usually not be employed because under theseconditions the crimping or bulking of the filaments is not permanent andutility of the fibers is reduced.

One of the essential elements of the process is that the filaments oryarn must be inherently elastic but must be rendered non-elastic andplastic in the turbulent atmosphere. The plastic condition may bebrought about by the temperature of the compressible fluid or in thefilaments. In any case, the plastic condition of the filaments must betemporary and transistory. The term plasticizing or plastic is intendedto mean that the conditions to which the term relates are such that thefilaments are in a temporary flaccid, non-elastic, deformable condition.After the plasticizing conditions are removed such as by lowering thetemperature, chilling, removing the solvent, or similar considerations,the filaments and yarns must return to their normal elastic state. Theuse of an inert compressible fluid such as air or steam under conditionswhich do not plasticize, soften, or render the filaments non-elastic,does not fall within the scope of the invention. Wet steam will fail toproduce configurations in the yarn described above if the temperature ofthe yarn does not reach a point sufficiently high to render it plasticand nonelastic. Under such conditions, crimps and crunodal loops may beformed but they are not stable and must be treated under plasticizingconditions to set and stabilize the crimps. On the other hand,relatively low temperatures may be used if there is sufficient residualvolatile solvent in the filaments. It will also be apparent that largeamounts of non-volatile plasticizers such as dibutyl phthalate,tricresyl phosphate, oils, plasticizing resins, etc., are relativelypermanent, and when these are present the yarns will not return to anelastic condition and should be avoided except for special purposes.

At high speeds and with certain polymers the fiber temperature should bewell above the second order transition temperature. A preferred minimumtemperature defined as a cold point is given by J. W. Ballou and J. C.Smith in the Journal of Applied Physics, vol. 20, page 499 (1949). Thecold point is the second inflection in the sonic modulus-temperaturecurve for the polymer or fiber in question. In general this temperaturemay be 50 C. or more above the second order transition temperature.

The temperature of the filamentary structure is difficult to measureunder the usual working conditions. At high speed it is indicated thatthe surface temperature of the fiber being treated may be well above thetemperature of the fiber interior. At low speeds, however, the

filamentary structure tends to come to equilibrium with the turbulentfluid temperature. The minimum temperature useful for treating thefilamentary structure at low speeds in the range of l to y.p.m. may beconsidered the minimum useful yarn temperature for the process of thisinvention.

To achieve maximum bulking or crimping it is essential that the tensionof the yarn subject to the turbulent fluid medium be maintained belowabout 0.1 gm./ denier. Preferably yarn tension during the bulking ismaintained between about 0.0001 and about 0.01 gm./ denier. For the mosteflicient bulking action at the highest degrees of bulk and highestthroughput of yarn, tension of the yarn should be maintained betweenabout 0.0005 and about 0.005 gm./denier. This low tension in the yarn ispreferably regulated by controlling the yarn feed rate vs. the yarntake-up rate so that the bulky yarn forms a shallow catenary between thejet and the downstream guide. The tension can also be governed by thedegree of forwarding or braking action of the fluid plasticizing medium.

Yarn feed speed can be varied over a considerable range depending on thematerial, temperature, denier, degree of bulking, tension and othervariables. For economic reasons (productivity/position) the feed rateshould be at least y.p.m. although slower speeds may be used forspecific items or special effect. Feed rates can run as high as 1000y.p.m. or even higher. Preferred feed rates are in the range of 100 to800 y.p.m.

The temperature of the heating fluid must be high enough so that eitheralone or in combination with some auxiliary plasticizing component,e.g., water, acetone or other solvent, it will soften or plasticize thefilamentary material passing through the heating area. The optimumtemperature, of course, varies depending upon the material beingtreated, the form of the material being treated; i.e., staple orcontinuous filament, the denier or yarn size, the rate of throughput,the degree of turbulence and/ or pressure of the treating fluid, thedesign of the treating chamber, and the degree of crimping desired. Thetemperature can range as shigh as 700 F. or more and a preferred rangeis 400600 F. The controlling factors are the characteristics of thematerial being treated and the temperature to insure permanence ofcrimp. The true upduring treatment. The yarn temperature during thecrimping operation should exceed the second order transition temperatureto insure permanence of crimp. The true upper limit, of course, is thetemperature at which objectionable melting and/or chemical degradationof a given yarn takes place.

There are a number of means and apparatus whereby a turbulentplasticizing fluid to achieve the improvements jets or devices fortreating a filamentary material with a turbulent plasticizing fluid toachieve the improvements of this invention are described in US.2,783,609 and copending applications Ser. Nos. 375,372, now US. 2,852,-906 to Breen, issued Sept. 23, 1958; 604,564, filed Aug.

10 16, 1956, by Hall, now Pat. No. 2,958,112; and 598,135 filed July 16,1956, by Breen and Sussman, now Pat. No. 3,009,309, as well as those inFIGS. 6 through 12.

It is necessary to cool the crimped yarns after treat ment in theturbulent plasticizing fluid and prior to any further operation thatimposes tension on the yarn bundle. This quenching, cooling, or freezingoperation is necessary to lock in the three-dimensional, random,curvilinear configuration imposed on the various filamen tary elementsby the hot turbulent fluid. This quenching operation should preferablycool the yarn below the second order transition temperature, T Aftercooling, the yarn can be subjected to normal processing tensions andwound into any of the conventional yarn packages. This quenchingoperation can be carried out by piddling into a sliver can or onto amoving belt or screen but from an economic viewpoint, it is preferred tocool the yarn on-the-run as an integral element of the over-all crimpingor buckling process. It is preferred to use a positive cooling operationeither immediately before or after the take-up roll-the important factoris that cooling is effected prior to imposing any substantial tension onthe hot plastic crimped filamentary material.

Adequate cooling of the yarn can be achieved by passage across a chilledplate or roll. Passage of the yarn through a suitable liquid bath willalso cool the yarn adequately. The preferred embodiment, however, is theuse of a flow of a cooling fluid-preferably a gas. This can be in theform of a jet that impinges the gas on the yarn bundle or it can takethe'form of the jets described previously for treating the yarn with ahot turbulent plasticizing medium. Cooling jets can be designed toforward the yarn, apply a braking action, or so designed and balancedthat they exert neither a forwarding action nor a braking action. Goodresults may be obtained if the quenching jet applies a braking action tothe filamentary material since this enhances and increases the amplitudeof the crimp by its action on the still plastic filaments on theupstream side of the cooling jet. The cooling jet may be at roomtemperature or even refrigerated.

The yarn overfeed should be adjusted so that the tension in theprocessing zone is in the range indicated above. The overfeed rate canbe as high as 250% or higher but for most yarns this value is from 15%to preferably above 30%.

The feed pressure of the hot plasticizing fluid will depend on thedegree of turbulence desired, feed speed, yarn denier, material beingprocessed, design of jet and the like. Pressures in the range of 20p.s.i.g. to 200 p.s.i.g. or more are useful while the preferred range isfrom 40- 100 p.s.i.g. Normally economics will dictate that the optimumpressure is the lowest that still gives the desired degree of crimpingIn US. 2,783,609 it is disclosed that the filamentary material should beremoved abruptly from the fluid stream. It has been found advantageousin the subject process to remove the filaments gradually from the hotfluid stream thus keeping the yarn hot for a longer period of time priorto quenching. The rapidly expanding fluid medium will also give acooling action outside of the yarn heating zone.

It is preferred that the feed yarn contain little or no twist. The twistlevel should be below 2.0 t.p.i. and preferably below 1.0 t.p.i. inorder to avoid formation of a regular helical-type crimp. Yarns ofhigher twist levels can obviously be processed; however, the tendency isfor the formation of stable loops and filament intertangling at theexpense of bulk and extensibility of the yarn bundle --thus the yarnbundles become increasingly compact as the twist level rises.

The process is well adapted for using a number of ends of yarn in thesame jet. Thus, it is possible to pass two to five or more ends througha single jet at the same time. The resulting yarn may have the ends wellblended or it may have bulked ends which will be distinctly separate andindependently windable depending on the processing conditions. Two ormore yarns may also be treated using different tensions or feed rates soas to produce a tensionstable bulky yarn with extensibility confined tothat of the shorter member. Likewise, two different types of yarn suchas nylon and rayon may be passed through the jet. The differentialshrinkage and heat-setting of the two types of yarn provides manyinteresting effects which are desirable for esthetic reasons in textilematerials. The crimp of the product is extremely stable and is notremoved by tensions up to the draw tension. The bulked yarns disclosedin US. Pat. 2,783,609 require a high degree of intertangling or twist inorder to maintain their bulk properties. The new yarns described hereare stable and keep their bulk even more when there is no entanglementor appreciable twist. Monofilament may be treated in a similar fashionto obtain a single crimped continuous filament. It is also to beunderstood that any treatment of yarns herein disclosed is to beconstrued as being applicable also to single filaments although forreasons of economy bundles of filaments or yarns are treated.

The process of this invention results in a gross increase in the bulk ofthe filamentary structures. The comparison of the starting denier to thefinal denier is a crude indication of the bulk increase. However, sinceyarn of a given denier may have an open bulky structure or may have avery compact structure, a better measure of bulk can be obtained bydetermining the weight of a definite volume of yarn. The yarn diametermay be measured and the weight per unit length may be determined ing./cm. Assuming that the yarn bundle is round, one may determine theyarn cross section in cm. Then by also determining the length per unitweight, one may calculate the bulk in cubic centimeters per gram(specific volume), The bulk of yarns prepared by this process is muchgreater than the bulk of yarns prepared by the process of US. 2,783,609. For example: the bulk of a yarn prepared by the process of thispatent from 2,000 denier feed yarn is about 7 cm. g. Yarns from thepresent process, on the other hand, have specific volumes in the range10 to 50. The comparison of the starting denier to the final denier isan indication of this bulk increase.

The synthetic filamentary materials to be treated by the process of thisinvention should preferably be in a high state of orientation to reducepilling in the finished fabrics. Drawable filaments tend to snag andpull out of the fabrics. The resulting fuzz fibers then tend to wind-upinto fuzz balls usually referred to as pills" in the finished fabric.When the oriented filamentary structures are passed under low tensionthrough the hot turbulent plasticizing fluid medium, a considerabledegree of deorientation and crystallization occurs.

Because of the unusually large increase in crystallinity, duringprocessing, the final yarns have a break elongation that is much smallerthan would be expected considering the large decreace in orientation.Similarly the tena city changes less than expected. At the same time,the yarns have a surprisingly high dyeing rate. The net result is toobtain unusual bulky yarns having a desirable combination of lowelongation, low pilling tendency, and rapid dyeability. Pilling isavoided because yarns of low elongation do not easily draw or pull outof the yarn or fabric when snagged to give long fuzz fibers. Theseundesirable fuzz fibers cause pilling by winding and entangling aroundone another until balls of fuzz are formed. Of course, yarns with lowelongations can be obtained in other bulk yarn processes by drawing thefeed yarn adequately, but these highly drawn yarns then have relativelylow dyeing rates.

In addition to the increase in relaxed yarn denier due to the convolutedform, the high degree of deorientation that accompanies the relaxationin a preferred process re sults in a gross increase in the filamentdenier of the yarn being treated. Some increase in denier, of course,ac-

companies almost any relaxation or bulking process, i.e., 110%. Thefilament denier of the new products formed by the subject process,however, increases in denier from 12. to 25% or more as compared to thefilament denier prior to treatment. In this instance, of course, denieris measured by the change in filament weight per unit length with thecrimp removed by a light tension, eliminating the denier increaseassociated with crimp contraction.

The yarns produced by the process of this invention are generallycharacterized by a very desirable tendency to develop increased crimpamplitude and yarn bulkiness as a result of mechanical exercisingfollowed by the application of heat and/or plasticizer to the yarn whileit is in a relaxed or low tension condition. These steps coincidegenerally with the normal treatments involved in the formation of theusual fabric types and in the subsequent dyeing and finishingoperations. The tufting opera tion in the formation of a tufted carpet,for example, applies momentary high tension to the pile yarn as thetufting needle forces the yarn through the backing fabric. The loop,once in place, is in a low tension or relaxed state as the hot-wetfinishing steps are used as for example, in piece dyeing of the carpet.The bulking action accompanying these treatments is particularlybeneficial in the tufted carpet since it causes the individual pileloops to increase their coverage of the backing material giving muchimproved appearance. The property of increasing bulk with the abovetreatments is not essential, however, because of the great bulking powerinherent to the extensible random curvilinear filament form. Ontensioning, for example, in the carpet tufting operation, thesubstantially continuous filament yarns of this invention are held in anessentially straight condition with a bulkiness little more than that ofa conventional yarn of similar weight and filament count. Upon releaseof the tension as the tufting needle is withdrawn, however, the elasticrecovery of the well-set crimp form causes the filaments to resume theirrandomly crimped configuration producing a great increase in bulk of theindividual tufts so that the backing material is effectively obscured.Yarn portions held against the backing fabric between adjacent tufts,how ever, remain in a low bulk tensioned condition. This gives adesirable preponderance of pile yarn on the face of the fabric and aminimum on the back. This applies similarly to other pile fabrics suchas those useful in upholstery.

In normal weaving and knitting operations, the bulking character of thisyarn is similarly beneficial. In sweater weight knit form, for example,the bulking action tends to obliterate undesirable threadiness. In wovenfabrics, this action gives improved covering power, a drier tactilequality, and increased fabric-to-fabric friction, as compared withfabrics of unmodified yarn.

Since tensioning and hot-wet finishing are important factors in theutilization of these yarn products, tests were devised to characterizethe response of the yarns to these treatments.

In general, these tests employ a lightweight skein of yarn equivalent toabout 5000 denier (measured through the double loop thickness). Withheavy yarns, a single loop will sufiice for the test. The length is cutto any value suitable for measurement of lengths in both the relaxed andtaut condition. A load of 0.5 gm./den. is applied to the sample. Theload is then reduced to 0.1 gm./ den. At this latter load, the samplelength is measured and recorded as L The weight is removed and thesample is treated with atmospheric steam until contraction ceases. Thesample length is remeasured and recorded as L The denier of the crimpedyarn is then measured in the relaxed state and recorded as Den A tautdenier value may also be calculated based on L Yarn crimp elongation isthen calculated as follows expressed as a percent increased in crimpedyarn length Crimp elongation is a measure of the extensibility of theyarn of this invention and its is to be understood that the terms arequalitatively interchangable. It is also a measure of crimp amplitudewhich in turn is a measure of yarn bulkiness provided the crimpfrequency is in a suitable range (-50 crimp/ inch) and random incharacter so that in-phase packing is eliminated. In general, for adesirable bulky yarn for the purposes of this invention a YCE of atleast is necessary and or more is preferred.

Since it is likewise desirable that true fiber shrinkage accompanied bymolecular deorientation be accomplished in a preferred embodiment ofthis invention this shrinkage has been determined as follows:

Den Den Percent shrinkage =[l 1x 100 Similar measurements may be appliedto single filaments. FCE will be understood to mean fiber crimpelongation. This may differ from YCE because of such factors asinterfiber friction, where Den is the denier of the yarn beforetreatment. In order that the greatly improved dyeability may be achievedat acceptably low yarn elongation values, it is necessary that the truefiber shrinkage accompanying this process be at least 12% and preferably25% or more.

Another parameter derived from the above measurements is useful incomparing yarns made at uncontrolled overfeed (FIG. 1 without rolls 41,42, 45, and 46), with those made with the double roll or triple rollsystems (FIG. 1 as shown). This has been termed the effective overfeed(EOF) and is calculated as follows:

Den 1 Denl 1 X100 All of the jets useful in the process of thisinvention are characterized by an arrangement for the common exit of theturbulent fluid and the yarn bundle being treated. The turbulent fluidin all cases exhausts at high velocity relative to the yarn velocity.One surprising quality common to all jets which are adjustable is theneed for careful adjustment of the jet for optimum bulking action. Thejet shown in FIG. 6 is easily adjusted by moving part 102 in or out withrespect to part 95. A second adjustment is accomplished with therotation of part 102 within the opening 104. In general, with heavyweight yarns, lip 105, on needle 103, should be withdrawn from thecenter position. For light denier yarns the optimum adjustment is withthe lip beyond the center line of opening 100. The needle obstruction inthe air flow also adds turbulence to the system which in some casesgives a superior product.

Jets shown in FIGS. 7, 8, 9 and 12 are also sensitive to adjustment. Ingeneral, the part (111, 116, 124, or 143) introducing the yarn to theair stream should be slightly off-center with respect to the orificeaxis for best bulking action. A 60 angle a (FIG. 6) favored ease ofadjustment for best bulking action. In the jet of FIG. 10 theeccentricity factor is provided by the abrupt change of direction of thehigh velocity fluid as it enters the yarn passage from one side. Avariation of this apparatus having several fluid entry ports spreadabout the periphery of the yarn passageway is likewise made eccentric inits action on the yarn by using ports of different sizes and/ or bydisposing them in a preferred unsymmetrical grouping. Sationary baffleswithin the jet may be used similarly to provide the eccentric flowpattern.

The following examples are given by way of illustration and notlimitation. It is to be understood that while they illustrate the use ofcertain synthetic polymeric yarns having certain cross sections thesemay be substituted by any other polymeric yarn or filament hereindisclosed having any cross section such as circular, square,rectangular, flat, star shaped, or those having three or more cusps andsimilar shapes. Likewise the denier, speed, temperature,

take-up speed and other considerations may vary widely within the limitsgiven above.

EXAMPLE I 8000-136 undrawn 66 nylon yarn with Y cross-section filamentshaving a modification ratio of 2.2 as in FIG. 22 was processed using theapparatus of FIG. 2. The yarn 51 was fed through a guide to feed rollsmoving at 133 y.p.m. to draw pin 54. From this pin the yarn was taken todraw roll 56 turning at a surface rate of 400 y.p.m. with a sufiicientnumber of wraps to draw the yarn and cause it to stretch 200%. From thispoint, the yarn was passed through jet 62, fed by 100 p.s.i. steam,superheated to 575 F. The bulked yarn was carried to step roll 58 havinga surface speed of 300 y.p.m. so that the bulking operation wascontrolled at 33% overfeed. The yarn was then carried to a wind-upsystem moving at 370 y.p.m. to give a dense package structure in whichthe fibers were held in a nearly straight condition. This yarn, whentested according to the above procedure, developed a crimpted denier of3200 and showed a yarn crimp elongation of 37%. The actual fibershrinkage was such that the average fiber cross-sectional area wasincreased 14%.

EXAMPLE II 8000-136 yarn with Y cross-section filaments having amodification ratio of 1.8 was spun from spinneret 71 FIG. 3 to rolls 74moving at 175 y.p.m. over pin 75 heated to 110 C. and then to draw rolls76 moving at 700 y.p.m. From these rolls the yarn was fed to jet 80operated with 105 p.s.i. steam superheated to 610 F. The bulked yarnexhausting from the jet was fed to rolls 82 moving at 500 y.p.m. andfrom there to wind-up roll 89 moving at 590 y.p.m. to give a hardpackage in which the filaments were essentially straight. After testingaccording to the above procedure, the bulked yarn denier was found to be2700 and the yarn crimp elongation was 14%. The shrinkage was 15%.

EXAMPLE III The process was operated in the same fashion as Example IIbut with the added element of the cold air quenching device 84 added asshown in FIG. 3. This gave a yarn with a bulked denier of 3400 and a YCEof 45% as measured by the above procedure. The yarn of this example wasmuch bulkier than that of Example II made without the quenching device.

EXAMPLE IV Yarn was bulked as in Example II but with a modified take-upsystem as shown in FIG. 1. This consisted of a tube 47 leading fromrolls 45, 46, to piddle barrel 49. Air flow entering through tube 48served to advance the yarn to the barrel allowing it to fall in atension free condition into the container. The tube was mounted on asuitable traversing mechanism so that the yarn built up in rewindablelayers. This yarn showed the same desirable properties as that fromExample III. Jet 36 was of the design as indicated in FIG. 6. Theorifice section 101 had a diameter of .076" and an intermediate diameterof .099". This jet operated in a superior fashion to the jet in whichthe entire orifice was of the larger 0.99" diameter.

The following examples are given in table form. The general procedure ineach of these examples is shown in FIG. 1. In Table II under thedescription of the yarn, the first number indicates the overall yarndenier, the second number is the number of filaments in the yarn, thethird number where present represents the twist in number of turns perinch. The letters Z and S represent the direction of the twist. Theletters R or Y following the S or Z twist indicate the cross section ofthe filaments, R representing round, and Y indicating the cross sectionsimilar to that shown in FIG. 22. The final letter or letters indicatethe luster in which D stands for Dull; SD for Semi Dull; and BR forBright. Unless otherwise noted the jet employed is shown in FIG. 6. Thefirst number refers to the value of a in FIG. 6. Unless otherwise notedthis value is 7. Of the remaining two letters, the first refers to theventuri size and the latter to the needle size, the values of whichappear below in Table I. The number under feed speed is yards perminute. The overfeed is the difference between feed rate and the take-uprate divided by the take-up rate and multiplied by 100 to obtainpercentage. Unless otherwise noted, the tension in all of the exampleswas just enough to draw the yarn away from the jet and in general wasless than grams. The steam pressure is expressed in p.s.i.g.

TABLE I Diameter Diameter 100, of 101, Fig. 6, inch Fig. 6, inch 5 Yenturi:

Needle OD, inch ID, inell 055 055 R 07G 070 S 009 076 U 009 099 125 112TABLE 11 Steam Percent Feed over- Temp. Yarn Jet speed feed Press F,

Number: 66 NYLON 1 15 monofil B/S 76 90 580 1 end, 7050l/2ZD A/R.. 560 2ends, 7050l/2ZD 60, A/R 85 595 1 end 7tl7l/2Z-D 70 575 2 ends,70-50-1/2Z-D S5 590 2 ends, 7CF34--1/2Z Y-SD... 85 560 4 ends,70341/2ZSD. 90 450 100-34 1 Z-SD 80 400 200-34-3/4Z -SD 90 450780-51-3/4Z-SD 90 450 3 ends, 780-51-3/4Z-SD 61 282 3 ends,780-51-3/4Z-SD.-. 60 510 3 ends, 780513/4ZSD 90 510 3 ends, 780-51-1.7Z-SD t 100 550 8401401/2ZSD 90 525 840-140-1/2Z-B R. 90 530 840-140-l/2ZB R- 90 530 840-140-1/2Z-B R 90 530 84W1401/2Z B R 85 5851,050-70l/2Z-Y-SD 90 550 1,560-104-0-R-B R 85 550 2,0001360.38Z-B R-R-85 530 2,000136-0.38ZB R-R- 100 350 2,0001360.38ZB R- 100 450 2,000-136038Z-B R-R 100 610 2,000-1360.38Z-B R- 85 600 2,000136l/2Z-YSD 90 550 2,0001361/2ZYSD. 90 550 2,000-136 1/2Z-YSD 90 550 2,000-136*1/2ZYSD 90550 2,000136l/2ZYSD 90 554 2,3001580*YBR 50 270 2,3001580YB R 64 2822,3001580YB R 295 2 300-158-0-Y-B R 75 298 2 300-158-0-Y-B R 60 3442,300-1580Y-B R 60 378 2 3001580YB R. 105 395 2,300-1580YB R 105 4182,3001580YB R 105 473 2,300158 0YB R. 105 560 2,3001580-YB R 12 2502,300-1/2Z-Y-SD 90 450 2,30012ZY-BR 64 300 2,300-1/2ZY-B R 90 3222,300-1/2Z-Y-B R 64 340 2,300l/2ZY-BR- 60 460 2,3001/2ZYB R. 60 495 2300-1/2ZYB R 64 460 2,300-1/2Z-Y-B R 460 2,300-158-0-Y-B R 80 4602,3001580YSD .i 90 550 2,300-158-1/2Z-Y-B R 100 550 2,300-1581.0ZYB R100 550 2,3001580Y-SD 90 550 2,300158-0YSD 550 2,300-158-0 Y-B R 63 4732,300-1582Z-YB R. 63 487 2,300-158-1Z-Y-B R. 63 454 2,300158*0.3SZYB R100 460 2 ends, 2,300*1581.8Z- Y 100 460 Undrawn, 4,000-158 0- 100 3852,5204201/2ZR- 100 460 3,O002001/2Z YSD. 550 3,000-2001/2Z-YSD 90 5504,000-2721/2Z-Y-SD. 90 550 1, l 48-86-0 356 2,0001361/2Z-YSD. 90 55468a. 2,000136l/2ZY-SD 100 602 YARNS OTHER THAN 66 NYLON DAC RON 602205005,600 60, A/S 42 44 85 580 1,100-250-0-51 0, 0/5.. 98 47 85 5721,1002500-51 60, C/S 98 47 85 570 ACETATE 72 1,800-88-0-BR D/U 50 75 90450 73 1,80088.25-BR D/U 200 60 80 400 TABLE IL-Oontinhled Air PercentFeed Overemp., Yarn Jet speed feed Press. F.

Number:

ORLON 78 2 ends, 100-40-0.3Z50 60, .A/R 50 42 60 300 BLENDS 79 1,800880BR Acetate, 1,050-79-0 SD Ny1on D/U 50 75 90 450 80 {2,000-1361/2Z-YSDNylon Plus 900-50 Rayon.- 81 2,0001361/2ZYSD Nylon 82 Plus 900-50 Rayon""5 38 82 {2,000-136-1/2Z-Y-SD Nylon-- .I N 38 Plus 900-50 Rayon .1 5082 90 422 83 55+45 Daeron-Woolec. 12Z T.P.I D/U 110 60 510 84"-. 2/28Turbo I 8Z-4S spun Or1on DU 42 0 550 85... 2/28 Turbo 8Z-4S spun Orlon 235 550 86 2/28 Turbo 8Z-4S spun Orlon 8 40 27 35 550 AIR-BULKED YARNNYLON 87 1,050-79-1/2Z-Y-SD D/U 50 76 85 130 88 2,0001361/2ZYSD D/U 5176 85 220 89 2,0001361/2ZYSD 10 50 76 85 320 90 2,0001361/2ZYSD 240 7685 440 91. 2,0001361/2ZYSD 900 85 800 92. 2,000l36-1/2ZYSD 900 85 640 932,0001361/2Z-YSD. 900 85 640 94 2,000l36l/2ZYSD 51 76 85 327 952,0001361/2ZYSD 51 76 85 353 96 2,0001361/2ZYSD 51 76 85 458 972,0001361/2ZY-SD 100 76 85 350 98 2, 000-1361/2ZYSD.- 150 76 85 530 2,0001361/2ZY-SD. 200 76 85 516 50 76 85 307 50 76 85 325 50 76 85 445ORLON 10R 10040-22 60, A/R 50 76 85 520 RAYON 109 1, 350-150-BR D/U 5076 85 325 ACETATE 50 76 85 190 50 76 85 211 50 76 85 355 50 76 85 461 5076 85 470 50 76 85 477 116 1, 800882SBR 200 76 85 375 117 1,800-88-2S-BR C/U 50 76 85 315 1 Maximum.

I Turbo is the trademark for a stretch-break process of the J. L. LohrkeCo.

In the above table the term Dacron is the trade name of E. I. du Pont deNemours and Companys polyester fiber. The fibers used in the table underthis designation were homopolymers of ethylene glycol terephthalate. Theterm Orlon is E. I. du Pont de Nemours and Companys trade name for theiracrylic fibers. The ones used in the table were copolymers containingmore than 85% acrylonitrile and intermediate amount of a modifyingcomonomer such as methyl acrylate and a small percentage, usually lessthan three of a vinylarenesulfonate such as sodium or potassium styrenesulfonate. The 6-6 type nylon is a term used in the art to designate thenumber of carbon atoms in the components of the linear polyamide, andthis type was used unless otherwise indicated.

In entries 11 and 12 of the above table the lower temperature produced ayarn of low bulk; whereas, the higher temperature produced a yarn ofvery high bulk. In entries 16, 17, and 18 the jet shown in FIG. 6 wasused in each case but the lip 105 was adjusted in three differentpositions. In 16, the lip was as shown in FIG. 6; in 17, the lip was inan intermediate position; and in the third case, the lip was near theopposite wall. The first adjustment resulted in a relatively high crimpof about 16 per inch. The intermediate position produced about 10 crimpsper inch and the third position produced only about 5 crimps per inch.In entry the turbulent fluid was saturated steam. Normally condensationor the presence of liquid in the turbulent zone should be avoided.

In entries 23, 2'4, and 25, crimps of 3, 8 and 15 per inch were obtainedby using temperatures of 350, 450, and 510 'F., respectively. In entry27, high bulk uniform crimp was produced; whereas, in entry 34 a lowerbulk was obtained due primarily to tension applied to the yarn in thebulking zone of about 40 grams instead of less than 5 grams as in thepreceding entries. In entries 32 to 41, temperatures below 350 F.required post tensioning to obtain maximum bulk. The optimum bulk inthis group is obtained with 10 to 15 crimps per inch at about 450 F.Above this temperature the bulk becomes less as the crimps becomesmaller and more frequent until fusion takes place above about 560 F.,under the conditions given in entries 3-2 41. Entries 44 to 50illustrate conditions under which the jet was allowed to bulk the yarnunder maximum overfeed with no take-up roll. In these entries the higherpressures produced higher bulk. At 50 y.p.m. at approximately 450 F. thehighest bulk was obtained. An increase in speed generally reduces bulkunless fluid temperature and/or fluid flow rates are increased. Entry 52produced a good bulk; whereas, entry 53 and 54 produced poorer bulkusing a diflerent jet, but the same yarn speed. Entries 55 and 56 bothproduced 'good bulk but the latter was slightly inferior to the former.

In entry 73 the yarn was fed directly from the spinning cell in theacetone plasticized condition to the turbulent fluid treatment. Thebulky yarn packaged in a low tension state was deplasticized at roomconditions for one week before use. It showed good crimped permanence.

Entries 57, 58, and 59 show that the yarn normally has less bulk as theyarn twist is increased. With respect to temperatures, bulking starts atabout 150 F. Up to about 300 F. the yarn is characterized by numerousunstable loops which are removed by tensioning. Above about 300 F. thepreferred yarn with greater bulk and few loops is obtained. At 50p.p.m., temperatures above 480 F. produce less bulk due to more frequentand smaller crimps. Entry '61 produced less bulk than entry 60. Entry 62using undrawn nylon produced a yarn with poor bulk for pile carpet usebut a suitable form of bulk for other applications such as upholsterystufiing materials. In entiy 63 the bulk was fair but there were to 8crimps per inch while in entry 64 the bulk was poor and there were 3 to4 crimps per inch. In entry 65, the yarn was excellent with respect tobulking and number of crimps and it will be noted the feed speed was 200y.p.m. In entries 110 to 112 as the temperature was increased the bulkbecame greater with a maximum bulking at 355 F. Entry 113-, where atemperature of 461 F. was used, showed slightly decreased bulk. In entry115, the bulk was low and in entry 116 the bulk was poor. In entry 117the bulk was high. In some entries such as No. 87 where the turbulentfluid temperature is less than about 300 F. the crimp is formed to givea bulky yarn, but the crimp is less permanent than is required for manypurposes. If greater crimp permance is desired, this may be imparted bya subsequent relaxed setting treatment.

In entries 8993 the jet of FIG. Was employed producing yarns which insome instances showed the alternating false twist form indicated in FIG.16. This is attributed to the twisting action of the T-shaped junction2.0 ducing a well oriented and highly crystalline yarn form. Entry 91was made at 900 y.p.m. using 800 F. air to produce a bulky extensibleyarn with 38% crimp elongation. Entry 92 was similar but the airtemperature was reduced to 640 F. and the yarn product showed reducedbulk and a crimp elongation of only 10%. In entry 93, 20 amperes at 5volts were applied to the preheater of the jet of FIG. 10, other factorsremaining the same as entry 92. The product of entry 93 showed greaterbulk than entry 92 and a crimp elongation of EXAMPLE V Three ends of a1000 denier-6-8 filament-zero twistbright 6-6 nylon (round filamentcross section) were passed simultaneously through jet of FIG. 8 usingthe process of :FIG. 1. The yarn passed over a feed roll at 110 y.p.m.just before entering the jet. It was bulked with turbulent superheatedsteam in the jet at 500 F, the steam pressure being 45 p.s.i.g. As itemerged from the jet it passed over a take-up roll at 76 y.p.m. so thatthe overfeed rate was The yarn was cooled in the surrounding air, andcollected as a piddle cake. The above feed yarn was obtained by colddrawing 6-6 nylon 400% (5 Additional 1000 denier feed yarns wereobtained by drawing specially prepared yarns at lower draw ratios (4X, 3X, 2.5 X and undrawn). Each of these 1000* denier feed yarns was steambulked under the same conditions as described for the 5X drawn yarnabove. The treated yarn properties are given in Table III. The undrawnyarns tended to draw in the turbulent steam rather than contracting; thebulked undrawn yarns, therefore, had high filament crimp elongation butthe denier decreased.

TABLE III.EFFECT OF DRAW RATIO ON STEAM BULKING OF 6-6 NYLON YARNS*Percent yam denier Filament crimp Bulked yam denier increase elongation,percent Denier per After After After filament tens. Piddled tens. tens.Filament After and 40% and and Before After shrinkage Piddled tensioningboil-01f overfeed boil-ofi Piddled boil-011 bulking bulking percent *Allyarns were run with 3 ends of 1,000 denier through jet. Total feed yarndenier was therefore 3,000. All yarns were run with 40.5% machineoverfeed, at 500 F., p.s.i.g., and 110 y.p.m. feed speed.

of the yarn and air holes in this jet and minor misalignment of the axesof these holes. The yarn form indicated in FIG. 16 may be preferred forfrieze yarns imparting an attractive texture to carpets or other fabricforms. Control of the length of the false-twisted zones may be achievedby employing a jet of the type shown in FIGS. 4 and 5 in which the airflow is pulse at suitable intervals. Other jets suitable for impartingfalse twist to the bulky yarn of this invention are disclosed incopending application Ser. No. 598,135, now U.S. Pat. No. 3,009,309. Thetwisting jets may be combined with the bulking jets or used in sequencewith them.

The yarn of entry 90 shows a variation of the above form. In this casethe yarn bundle shows divided regions characterized by oppositedirections of twist in the adjacent portions as indicated in FIG. 17.This is caused by the double eddy at the T junction of the jet of FIG.10 indicated in FIG. 11. For those uses where maximum bulk is desiredthe false-twist structures of FIGS. 16 and 17 should be avoided.

In entry 70 the feed yarn of polyethylene terephthalate was prepared bya warm, wet, drawing process such that the filaments were maintained ata temperature during drawing below the second order transitiontemperature. This produced a well oriented but essentially amorphousyarn product. The crimp permance of the product of entry 70 was superiorto that of the product of entry 71. Entry 71 feed yarn differed fromentry 70 feed yarn only in respect to the drawing method used. In entry71 a draw pin heated to 230 F. was used to stretch the yarn pro- Thedyeing rates of the steam bulked yarns and of the feed yarns weredetermined by dyeing at the boil for 60 minutes with 2% of an acid dyeColour Index number acid blue 165, 2% of a polypropylene oxide levelingagent and 2% Duponol 2 RA surface active agent (percent based on fiber).The percent dye on the fibers was determined by ultravioletspectrophotometry using solutions of the fiber in formic acid andmeasuring percent light transmission at 550 millimicron wave length. Thesteam bulked yarns dyed at a faster rate than the feed yarns. Part ofthis increased dyeability was due to deorientation of the molecularstructure in the drawn yarns as evidenced by increased elongation andlower tenacity (see Table IV). But this deorientation did not accountfor all of the increase in dyeability; the steam bulked yarns had muchhigher dyeability than feed yarns with the same percent elongation. FIG.19 shows the dyeing rates of feed yarns and steam bulked yarns as afunction of break elongation. Curve A shows the relation of dyeing rateto filament break elongation in untreated 6-6 nylon yarns prepared atvarious draw ratios. Curve B shows the relation of dyeing rate to breakelongation in a series of bulky yarns of this invention. Filament crimpelongation was not included in the break elongation. The dyeing rateswere increased still more than shown in Curve B by using higher fluidtemperatures, higher pressures or longer exposures The Colour Index,1956. 2 Trademark of E. I. du Pont de Nemours and Company for a sodiumalkyl sulfate surface active agent,

in the jet (higher overfeeds, lower feed speeds). Conversely, milderconditions gave somewhat slower dyeing rates. Curve C representstheoretical yarns having 50% greater dyeing rate than the untreatedyarns of Curve A. The preferred yarns are represented by thecross-hatched area above Curve C in FIG. 19. At the same time, thepreferred yarns should have less than 200% elongation to reduce thepilling tendency in fabrics. The preferred non-pilling yarns lie to theleft of Line D in FIG. 19.

Bulked yarns having high filament break elongations tended to pillreadily in carpets as shown in FIG. 20. The pilling index is a numberwhich was determined by sub jective rating using a test panel. An indexof is completely unacceptable, index of 3 is borderline acceptable,

ercised. At higher speeds the crimps per inch developed in the processwas less than at low speeds (Nos. 5 and 6). Single ends or triple endswere passed through the jet with equal success (Nos. 7 and 8). Higherpressures tended to give higher crimps per inch because of the greaterthrough-put of heat in the jet. Monofilament was easily processedthrough the system as shown in No. 10. Hot air was equally effective andproduced good bulk yarns as shown in No. 11. The superior bulkingquality of Y over round cross section is shown in No. 12 and No. 13. Theyarn with Y cross section increased 99% in denier while the yarn withround cross section increased only 67%. The percents increase infilament denier in Nos. 4, 7, 8, 12, and 13, are 38, 70, 29, 11, and 7,respectively.

TABLE V.-EFFECT OF PROCESSING CONDITION ON GEOMETRY OF BULKED YAR S FR M4 DRAWN 6-6 NYLON N 0 X [All feed yarns were BR luster except as noted]Bulked product (after tensioning Feed yarn Processing conditions andrelaxed boil-ofi) Percent Fiber Yam 1 No. Machine Feed increase crimp orCross overfeed, speed, Temp., Press, Yarn in yarn elong., Crimps/ fils.Twist section Jet fig. percent y.p.m. F p.s.i.g. denier denier percentin.

158 0 Y (2.2MR) 7 37 200 603 108 4, 340 89 59 10. 7 158 0 Y (2.2MR) 7100 200 610 108 5, 169 125 110 11. 1 158 0 Y (2.2MR) 7 150 200 610 1085, 188 126 115 12. 9 158 0 Y (2.2MR) 5 6 100 460 110 6, 945 202 131 16.5 138 0 Y (2.2MR) 7 100 200 575 85 4, 729 137 86 14. 9 138 0 Y (22MB) 7100 400 600 85 4, 071 104 82 9. 8 51 0. 75Z R 6 100 50 460 100 1, 760126 53 19. 6 51 0. 75Z R 6 100 50 450 100 5, 979 158 101 18. 2 68 0 R 740. 5 110 500 45 4, 660 37 8. 9 0 R 6 75 50 580 90 22 110 18. 0 136 0.5Z Y (2.2MR) 5 6 76 50 353 U 85 5, 395 170 152 21. 0 68 0. 4Z 7 41 110500 45 5, 022 67 59 7. 9 68 0.4Z Y (2.2MR) 5 7 41 110 500 45 5,975 99116 11.1

1 A single end of yarn was used in all cases except as noted. 2 Threeends of this yarn were used. 3 1 Monofilament. 4 18.3 denier perfilament. 5 These feed yarns were SD Luster. Air was used as theturbulent fluid.

All entries were prepared using steam as the turbulent fluid except asnoted. and index of 1 indicates no pilling. The carpet samples EXAMPLEVII Three ends of 780 denier-51 filament--0.75Z twist roundbright 6-6nylon were passed through the jet of FIG. 8 with 75% machine overfeed 50y.p.m. feed speed at 508 F., 85 p.s.i.g. steam. The steam bulked yarnand the feed yarn were examined by X-ray techniques, using just enoughtension to straighten the yarn crimp. The steam bulked yarn had a higherorientation angle than the feed yarn. The orientation angle wasdetermined by measuring the degrees of angle of the inner equatorial areat half maximum intensity. The are increases as orien- TABLEIV.-DYEABILITY VS. PHYSICAL PROPERTIES OF FILAMENTS BEFORE AND AFTERSTEAM BULKING [All yarnsdycd at boil before physical testing-0.1. AcidBlue 165 dyeing at boil min.]

Percent dye Tenacity Break elongation Initial absorbed (GPD) percentmodulus, GPD Before After Before After efore After Before After rawratio: D 1X 1.64 1.65 1.56 1.30 413 326 11.4 8.9 0.04 1. 11 3.65 2 90135 137 27. 9 14.3 0. 43 1. l6 4. 29 4. 18 103 118 30. 3 17. 3 0. 37 0.90 5. 35 5. 54 67 80 28. 6 20. 6 0. 30 0. 86 7. 80 7. 30 63 73 38. 0 20.0

EXAMPLE VI tation decreases. The inner equatorial arcs were 17 and Anumber of bulked yarns were prepared from 4X drawn 6-6 nylon. Theprocessing conditions were adjusted to give a wide range of usefulbulked products. The effect of processing conditions on the geometry ofthe bulked products is shown in Table V. At low overfeeds, the increasein yarn denier (after exercise and boil-off) was greater than themachine overfeed. For example, 37% machine overfeed gave a boil-01f yarndenier increase of 89%. At high overfeeds, the actual yarn denierincrease tended to be less than the machine overfeed because of theunstable loops which pulled out when the yarn was ex- 13, respectively,for steam bulked and feed yarn. The crystallinity of the feed yarn washigh but the crystallinity of the steam bulked yarn was much higher. Theincreased crystallinity was also shown by an increase in the fiberdensity. The density of the steam bulked yarn was 1.148 and of the feedyarn was 1.145. Additional information on orientation was obtained bymeasuring the birefringence of filaments from a steam bulked yarn andfrom a feed yarn. The birefringence decreased in the steam bulkingoperation from 0.0628 to .0598, showing that deorientation had occurredand that this deorienta- TABLE VII.IROCESSING CONDITIONS 161V 24 whichwas stable outside of the yarn bundle. The considerable increase in bulkwhich was obtained is shown by the increase in yarn denier and fibercrimp elongation in Table VII.

All of the bulked yarns had filaments with random threedimensional,nonhelical, curvilinear crimp. The crimp was inde endent in eachfilament and did not coincide with adjacent filaments.

D CHARACTERISTICS OF BULKED YARNS PREPARED FROM A VARIETY F SYNTHETICPOLYMERIC FIBERS Bulked product (as produced) Feed yarn Processingconditions Mach. Flber Yarn No. Den. over Feed Percent crimp den. of perJet of feed, speed Temp., Press, Yarn inc. in Den. per elong., Crlmps/Polymer 1 end fils. Twist fila. Fig. 6 percent y.p.m. F. p.s.i.g. den.yarn den. filament percent in. Polyethylene 1, 100 250 4. 40 D/U 50 110495 90 1, 620 47. 3 4. 44 43. 9. 2

terephthalate (Dacron). Polyacry)lonitrile 100 40 0. SZ 2. 50 D/U 26 38408 48 378 26. 0 2. 58 52. 5 10. 1

(Orlon Cellulose aeetate 1,800 88 20. 4 D/U 60 200 400 80 2, 686 29. 0l8. 9 47. 5 9. 8 Viscose 2, 700 150 0 18.0 D/U 97 50 415 95 3, 384 24. 017. 5 36. 5 7. 2

Norm-A single end of yarn was used in each entry except entry 2 in whichcase three ends of this yarn were used. The feed yarns in entries 1 and2 were SD Luster and in entries 3 and 4 the feed yarns were BR Luster.All entries were prepared using steam as the turbulent fluid.

Considerably more information was obtained by studying the low angleX-ray patterns by the methods of W. O. Statton as described in J.Polymer Sci. 22, 385 (1956), Crystallite Regularity and Void Content inCellulosic Fibers as Shown by Small Angle X-Ray Scattering. The lowangle pattern showed a higher amount of crystallite placement regularityin the steam bulked yarn when compared to the feed yarn. At the sametime there was a great increase in the long space distance betweencrystallites along the fiber axis. The steam bulked yarn had a longspace distance of 98 angstrom units and the feed yarn had a spacing of86 angstrom units. The lateral order of the long lattice structure wasvery high in the steam bulked yarn and only moderate in the feed yarn,indicating greater distance between crystallites across the fiber axis.Long space distance along the axis can be adjusted to any value in therange 86 to 120 angstroms by adjusting the processing conditions. Highertemperatures and longer exposures give greater long space distance. Itis preferred that the treated yarn have a long space distance at leastfour angstroms greater than the feed yarn.

EXAMPLE VIII A 2100 denier 6 nylon yarn having 112 filaments and zerotwist was passed through the jet shown in FIG. 6 The machine overfeedwas 100% and the feed speed was 200 y.p.m. Three different processingtemperatures were studied: 375 F., 435 F., and 515 F. The yarn processedat 375 F. had only moderate bulk. The yarn processed at 435 F. had highbulk and the yarn processed at 515 F. had very high bulk. Using this jetand this feed speed, it was not possible to process the yarn attemperatures as high as 550 F. without melting the yarn. The propertiesof the bulked yarn are show in Table VI.

EXAMPLE X A 6-6 nylon yarn having 2000 denier68 filaments zerotwist-round cross section was passed through a pad bath containing dyeliquor before going to the steam jet. The pad bath contained thefollowing material:

Water 1000 Benzyl alcohol 35.0 Duponol surface active agent 0.25Ammonium acetate 4.0 Anthraquinone Green GNN C.I. No. 1078 10.0

EXAMPLE XI The dyeing rate of a steam bulked yarn was compared to thedyeing rate of a feed yarn and of unbulked yarn which had beenautoclaved at 30 p.s.i.g. for one hour at 265 F without bulking. Thefeed yarn was 780 denier- 51 filament0.75Zround-bright 6-6 nylon. It wasbulked in the steam jet using 75% overfeed and y.p.m. feed speed. Thesteam temperature was 500 F. and the pressure was 90 p.s.i.g. The yarnswere dyed separately for ten minutes at the boil with 2% AnthraquinoneBlue ND RELAXED BOIL-OFF Filament shrinkage,

Filament percent crimp Crlrnps Denier (based on Bulked clung, per peroriginal yarn percent inch filament filament denier EXAMPLE IX SWF 2%polypropylene oxide leveling agent and 2% A number of differentpolymeric synthetic yarns were processed as shown in Table VII. In eachcase a bulky product was obtained. Some of the yarns had unstable loopswhich were pulled out by exercising, but the individual filaments whenremoved from the yarn had crimp Duponol RA (all based on fiber). Thebath was at a neutral pH and the bath to fiber ratio was 250:1.

The percent dye on fiber was determined using the tech- C.I. prototype12.

niques of Example V. The analytical data are shown in Table VIII.

The 'data in the table show that the yarn which was bulked at 500 F. had128% faster dyeing rate than the untreated feed yarn. The yarn treatedin autoclave had a much lower improvement in dye rate than steam bulkedyarn. The autoclave treatment was similar to the practice used inheat-setting frieze yarns for carpets.

EXAMPLE XII The improved uniformity in dyeing which is obtained in theproduct of this invention was demonstrated in the following manner. Thefeed yarn was 1000 denier- 68 filament-.38Z twistY (2.2MR) crosssectionsemidull 6-6 nylon. Samples of yarn taken from several pirns wereair textured at room temperature by the method of US. No. 2,783,609 toBreen, issued Mar. 5, 1957, and were then tufted side-by-side incarpets. The carpets were dyed with 1% Anthraquinone Blue SWF as inExample XI. Various yarns in the carpet from different pirns showedseveral shades difference after dyeing. Yarns from the above pirns werebulked in steam by the process of this invention using three endsthrough a jet at 75% overfeed, 200 y.p.m., 565 F., and 85 p.s.i.g. Theresulting steam bulked yarns were tufted side-by-side in carpets anddyed with Anthraquinone Blue SWF. There was no discernible yarn dyestreaks in the tufted carpets after steam bulking.

EXAMPLE XIII The superior bulk of steam bulked yarns in carpets wasdemonstrated by preparing carpets with staple yarn and carpets withsteam bulked yarn in which the polymer was 6-6 nylon. A three-ply cottonsystem staple yarn prepared from d.p.f. nylon was tufted to preparecarpets having several different weights of yarn in the pile (dependingupon number of stitches per inch). All carpets had 0.43" pile height.Similarly, steam bulked yarns were put into tufted carpets. The steambulked yarn was prepared from one end of 2000 denier-136 filament-.38Zroundbright6-6 nylon using 100% overfeed, 200 y.p.m., 575 F. and 90p.s.i.g. The work required to compress carpets (4 sq. in. in area) ofthe steam bulked yarn and of staple yarns to 10 p.s.i. was determinedusing an Instron testing machine. The work required to compress staplecarpets of various weights and steam bulked carpets of various weightsis shown in FIG. 21. The steam bulked yarns were much firmer to the handin carpets of identical weight and this observation was confirmed by theInstron tests. Consequently, carpets with 25% to 30% less yarn wereneeded for steam bulked continuous filament yarns to get the sameperformance as staple carpets. In FIG. 21, Curve A shows the workrequired to compress carpets of various weights prepared from stapleyarns. The total take-up in FIG. 21 is the weight of tufted yarn in asquare yarn of fabric and does not include the jute backing. Curve Bshows the work required to compress steam bulked continuous filamentyarns in carpet.

EXAMPLE XIV a feed speed of 150 y.p.m., a steam temperature of 450 7 F.and steam pressure of 50 p.s.i.g. were used.

Item B.-70-34-1/2Z semidull yarn (Y cross-section yarn with 1.9modification ratio) processed exactly as above.

Item C.70-34-1/2Z semidull filament nylon unbulked control. The threeyarns (A, B, and C) were woven as filling yarns with a pick gear of 72in a stock nylon warp of 70-34-7Z semidull nylon reeded 104 ends perinch. Fabric was crab-scoured at the boil, frame dried and heat-set at390 F., 20 second exposure, 5% under wet 'width and no overfeed. Yarncrimp properties are given in Table IX and fabric properties in Table X.

TABLE IX Yarn A Yarn B Yarn 0 Fiber crimps per inch 8. 3 17. 9 0 1 Fibercrimp elong. (percent) 5. 4 12. 5 0 1 1 As produced.

TABLE X Fabric Item A Item B Item 0 Finished construction (warp-fill.)114 x 76 x 76 118 x 78 Finished weight (Oz./Yd. 1. 92 1. 96 1. 99 Fabrlcthickness (inch) 0. 0055 0. 0050 Opacity:

IR (Percent light reflected) 52 58 57 I (Percent light transmitted) 1311 10 Fabric friction (vs. wool blanket) 0. 53 0. 63 0. 47

Of these fabrics, Item B is preferred to Items A and C and Item A ispreferred to Item C. Item B has greater bulk, opacity and friction.Friction of the fabric against a blanket is high enough to give improvedperformance as a sheet fabric, whereas, Item C does not approach thefriction requirements for satisfactory sheet fabrics. The greater bulkand friction of Item B gives a pleasing, dry handle resembling that ofsilks, and these properties are desirable in apparel fabrics such asblouses and slip fabrics.

EXAMPLE XV Item A.840-1/2Z-700 bright nylon yarn was processed with thejet of FIG. 6 having a U needle and a C venturi. An overfeed of 44.6%, afeed speed of y.p.m., a steam temp. of 440 F. and a steam pressure of 85p.s.i.g., were used.

Item B.840l401/2Z700 bright filament nylon un'bulked control yarn. Thesetwo yarns were knit on a 6-cut circular knitting machine (Jacquard)using a halfcardigan stitch. Fabrics was finished by scouring at theboil for 15 minutes in a detergent solution followed by rinsing anddrying in a hot-air tumble drier.

Fabric properties are tabulated in Table XI.

Item A shows a marked improvement over Item B in bulk and opacity. Thefabric has a pleasing, woollike hand and is scroopy and resilient inhand as compared with the unattractive hand of the control.

EXAMPLE XVI A bulk yarn prepared from 2700 denier-180 filament- 5 zerotwist 66-nylon was prepared by the conditions of Example VIII (515 F.).This yarn was put into an upholstery construction. The backing yarnswere high twist /2 cotton. The filling yarns were 12/2 cotton. Theweaving construction was 18.7 pile ends per inch, 56 back ends per inch,17 picks per inch, and the reed width was 55 /2 inches. The gauge wirewas 0.10 inches. A similar upholstery material was prepared from theuncri'mped yarn. This unbulked material required 21 picks per inch toget the same optical cover as was obtained using the bulk yarn.

EXAMPLE XVII A nylon tow of 80,000 denier and 20,000 filaments was fedat 2 yards/min. to a jet similar in cross section to FIG. 8. This jet,however, was elongated in a direction perpendicular to the plane of thecross section so that the yarn opening 119 was a slot four inches wide,and orifice member 117 was provided with an orifice in the shape of asimilar slot, likewise four inches in width.

The orifice angle a. was The tow was fed to the jet in a flattenedribbon form so that all parts of the yarn opening and jet orifice werefilled in a substantially uniform fashion. The turbulent fluid was 70p.s.i.g. steam, heated to 550 F. The bulked tow had a relaxed denier ofabout 15 0,000. Filaments removed from the tow showed an average FCE of86% and a fine uniform crimp of 22 crimps per inch. In relaxed form,this product had a bulkiness of 70 cm. per gram. It showed a fabric-likecohesiveness in both lengthwise and widthwise directions. Although theprocess rate in this example was low (2 yards/min.) the high denier(80,000) was such as to give reasonable productivity expressed indenyards/ min. which is the product of denier times yards/ min. In thisinstance the productivity was 160,000 denyards/min.

EXAMPLE XVIII ends of 2000-156 nylon yarns were fed to the jet ofExample XVII through a comb-like multiple guide within the opening 119so as to maintain the yarns separated from each other prior to contactwith the turbulent fluid. Other factors were the same as Example XVII.The 40 ends were wound as individual bulky yarns on a spool in the formof a warp sheet. The ends retained their individuality and could be fedto individual needles of a fabric-tufting machine.

EXAMPLE XIX A 15-denier 66 nylon monofilament yarn modified as in entry1 Table II was knit into a full-fashioned sheerhose using a 60-gaugeknitting machine set at courses per inch. A similar hose was constructedof the unmodified monofilament. The garment made from the modifiedmonofil showed a subtle crepe-like texture and a subdued luster. It alsoshowed a moderate amount of stretchiness, improved form fittingcharacteristics, and freedom from bagging at the knee as compared withthe unmodified control.

There is a well-defined relationship between the diameter of the yarnbeing treated and the diameter of the jet orifice which produces theoptimum bulking. Table IX shows several examples of a preferred jet fora given type of yarn. From this material, it may be inferred that theoptimum orifice is between about 1.5 and 10 times the diameter of theunbulked yarn, with a preferred range of between 2 and 6. For heaviestdenier yarns bulked at highest speed, the optimum diameter sometimes istoo small to allow the turbulent fluid to exhaust as freely as isdesired. Accordingly, it is sometimes preferred to provide separateexhaust ports for the texturing fluid around the periphery of theorifice. These exhaust ports should be kept small and should bepositioned at an angle to the yarn path so that the yarn does not tendto exhaust through them. For good operability it is important that theyarn path through the jet should be relatively unobstructed and smoothto prevent snagging and choking.

TABLE XII Jet Nylon Yarn orifice yarn. diameter, diameter, Remarkscount; mils, rni bulk yarn 10 55 High. 10 76 Medium. 8 76 Do. 8 93 Low.17 76 High. 17 99 Medium. 27 76 High. 27 99 Medium.

Conversely a uniformly controlled degree of choking seems to bedesirable. This is associated with the filaments splashing against theinterior wall of the venturi and can be controlled by careful adjustmentof the yarn tube position with respect to the orifice. The splashing caninitiate convolutions which tend to be restricted in their passageparticularly through the smaller diameter region of the jet orifice.Factors affecting friction between the filaments and the jet wall suchas yarn finish and surface roughness of the jet wall tend to influencethis effect. Eccentric fluid forces within the jet tending to throw thefilaments against the jet wall are similarly influencing. The initiatedconvolution may then be increased in amplitude during the passage of theyarn through the venturi particularly when the exit angle or.illustrated in FIG. 6 is relatively large.

It will be noted that in the several jets shown in FIGS. 6 through 12that the yarn enters at an angle to the air stream in some cases andco-axially in others. These jets operate in similar fashion irrespectiveof this feature indicating that the angle of entry is unimportant. Thesejets also have the common feature that the air and yarn exhaust togetherbut the process is operable with even such extreme variations in jetdesign as indicated in FIG. 10 wherein the entry port for the turbulentfluid 142 is continued beyond the yarn passageway in such a manner thatthe turbulent fluid exhausts preferentially through an orifice coaxialwith hole 142. In this case the yarn entry angle to the air stream isand the yarn exhausts from a port other than the exhaust port for theturbulent fluid. Similarly several entrance and exhaust ports for theturbulent fluid may be located at intervals along the yarn passage withentrances and exhausts either aligned or staggered. The entrance of thefluid in this case may also be in the same or opposed directions in asingle plane or in a number of planes passing through the axis of theyarn passageway. Fluid ports in jets of this design may be disposed atany desired angle to the yarn.

Throughout the series of examples there is considerable variation inyarn composition, yarn denier, yarn speed, steam temperature, and steamflow rate. These variables can be correlated through considerations ofheat transfer. For complete setting, a certain minimum temperature mustbe experienced by the yarn. Within 66 nylon this temperature is in theorder of 300 F. At high speed, with heavy denier yarns the mass flowrate of the yarn can be so great relative to the mass flow rate of steamthrough the jet that in suflicient heat is available to bring the yarnto the desired temperature. This can be expressed in the form of anequation as follows:

T =Superheated steam temperature T =Desired yarn temperature T =Startingyarn temperature HC =Heat capacity of steam HC =Heat capacity of yarnMFR Mass flow rate of steam MFR =Mass flow rate of yarn T should be atleast about the second order transition temperature (T and preferablyabove the (cold point) of the polymer in question as hereinbeforedefined.

The above equation indicates the importance of preheating since a yarnpreheater in effect increases T and reduces the value of T T In the highspeed examples given in Table II entry No. 93, it was necessary to usethe preheater built into the jet design (FIG. to get effective bulking.This helped to compensate for the limited steam flow rate inherent tothe jet design and dimensioning. It may, also, be noted that the steamtemperature (800 F.) used at very high yarn throughputs was far abovethe yarn melting point. Accordingly temperatures well above the meltingpoint of the yarn are operative.

Care must be taken, however, to avoid excessive heating of the yarnsince this tends to produce a fused product with filaments stucktogether reducing bulk and imparting undesirable hardness or in severecases a yarn no longer useful in normal textile applications.

The mathematical relationship indicating the upper limits of heating arenot as readily defined since the efficiency of heat transfer between thehot fluid and the yarn can vary over wide limits. Calculation indicatesthat the efficiency level in the preferred process is at least 50%. Thisis indicated in the following equation.

In this case, T represents the crystalline melting point of the fiberbeing tested or the interfiber fusion temperature if this is lower.

The bulky multifilament yarn of this invention has the desirableproperties of spun staple yarn and avoids the necessity of cuttingcontinuous filaments into staple and then reforming the staple intoyarn. The continuous filamet bulky yarn is simply and economicallyprepared, by process which requires little equipment, directly from thecontinuous filament bundle produced initially in synthetic fibermanufacture. The bulky yarn is superior to spun staple for many purposesbecause of its freedom from loose ends. The hand of fabrics made fromthe bulky yarn usually is stiffer than that of corresponding staplematerials, making them more suitable for use in draperies, suits,overcoats, etc. As discussed previously staple yarns can be processed bythis invention to improve bulk and achieve special effects.

The yarn is sufficiently uniform to be handled easily by textilemachinery and to form highly uniform fabrics without the sacrifice ofbulk or fiber interlocking characteristics that occur with somemechanically crimped yarns having too regular a structural pattern. Theyarn has been used without difficulty on both automatic weaving,knitting, and tufting machines. The increased covering effectiveness offabric made with the bulky yarn permits the production of more fabricfrom the same weight of yarn and, in addition, by greatly extending theutility of artifical fibers, enables them to replace expensive or scarcefibers in many uses. An additional saving in yarn weight is realizedintufted material since the crimp is largely removed by tension providedin tufting so that much less yarn is used on the reverse of the basematerial. The relaxed yarn on the front side of the fabric, of course,will still have its high crimp and bulk.

The low denier yarns and monofils can be used in any normal textileoperations and end uses. They are particularly useful in the preparationof very light fabrics because of the greatly increased bulk and coveringpower per unit of weight. The heavy denier yarns have many uses normalto such yarns and are particularly suited as the pile element of pilestructures. They can be used as cut or loop pile in garments and rugs orcarpets. The high bulk permits the production of woven or tufted carpetswith much improved cover and resilience. The absence of loose fibersalso makes such structures very pillresistant.

Another advantage is the suitability of this process for combiningfilaments of extremely fine denier into light bulky yarns, having ahighly uniform appearance, for which there is no spun staplecounterpart. More than one kind of filament may be processedsimultaneously to create yarn with a desirable blend of fibercharacteristics. Intermittent impulsing of the multifilament beingprocessed can be used to produce a novelty yarn having alternatingsmooth lengths and bulked regions produced according to the describedprocess. This can be accomplished by varying feed tension, feed rate, orfluid flow. A simple apparatus for achieving this effect is disclosed inSer. No. 610,546, filed Sept. 18, 1956, by Field, now Pat. No.2,931,090.

The simplicity of the new process permits its use at any point in yarnmanufacturing or winding with no interruption of processig routine adlittle outlay for new equipment. Distinct advantages of the process arethat it requires little supervision, demands very little maintenancebecause of its freedom from moving parts, and does not require humiditycontrol.

It will be apparent that many widely different embodiments of thisinvention may be made without departing from the spirit and scopethereof, and therefore it is not intended to be limited except asindicated in the appended claims.

We claim:

1. In the process of imparting a persistent crimp to synthetic linearpolymeric filaments of a yarn by feeding the yarn to a stream of acompressible fluid, jetted into a jet device at 20 to 200 pounds persquare inch gage pressure and at a temperature of at least about 400 F.to form a turbulent plasticizing region, and then taking up the yarn,the improvement for the preparation of continuous filament yarn having abulkiness greater than staple yarn spun from comparable fibers, whereinthe improvement comprises feeding 0 to 1 turn per inch twist yarn ofsaid continuous filaments eccentrically to the stream so that the yarnentering the stream is subjected to eccentric fluid forces, the yarnbeing fed at a rate at least 30% greater than the yarn take-up speed sothat the filaments are separated and whipped about by the stream in theturbulent region, removing the filaments from the hot stream before thetreated yarn has travelled appreciably beyond the jet device and thencooling the filaments under low tension, to crimp the filamentsindividually, and thereafter cross-winding said yarn into a package.

2. The process of claim 1 in which the filaments, after cooling underlow tension, are tensioned to remove any loops and the yarn is wound-upunder tension to form a package.

3. The process of claim 1 in which the fluid is air.

4. The process of claim 1 in which the fiuid is steam.

5. The process of claim 1 in which the filaments are made of acrystallizable thermoplastic synthetic linear polymer.

6. The process of claim 5 in which the treated filaments have a lowerdegree of orientation and a higher degree of crystallinity than they hadbefore the fluid treatment.

7. The process of claim 5 in which the filaments be fore treatment aresubstantially amorphous and oriented, and after treatment with theturbulent fluid are crystalline and oriented.

8. The process of claim 1 in which the yarn travels at a rate greaterthan about 200,000 den-yards per minute.

9. The process of claim 8 in which the yarn is of more than 50,000denier.

1-0. The process of claim 1 in which the filaments are passed directlyfrom the spinning operation to the fluid stream.

11. The process of claim 1 in which the crimp configuration of thefilaments is equivalent to a filament crimp elongation of at least 15%.

12. The process of claim 1 in which the feed yarn is

